Bleeding of epoxy resin around surfaces undergoing bonding during elec
tronic packaging assembly has long caused sporadic yield loss. Previou
sly. it was thought that vacuum baking reduced the yield lass resultin
g from surface cotaminants. Although vacuum baking inhibits epoxy resi
n bleeding, it a so produces coatings of hydrocarbons, which affect su
rface wettability and surface energy. Surfactant coating results in a
surface chemistry similar to vacuum-baked substrates but is a better a
lternative because of its controllability.